22 Southern Gardener^ s Practical Manual 



In the orchard and vineyard, plants are propagated 

 true to variety by division, while in the garden, with 

 the exception of those species which are propagated by 

 bulbs, tubers or tuberous roots, we are dependent upon 

 seed for growing our vegetables. 



ROTATION OF CROPS 



This should be systematically practiced in every well- 

 conducted garden. The i-easons for this practice are 

 based on sound scientific principles. 



A proper rotation maintains good physical condition 

 or good texture. This may be accomplished by very 

 heavy annual applications of animal manures. 



Different species of plants take from the soil the 

 elements of plant-food in different proportions, hence 

 the continued cultivation of the same crop on a soil may 

 exhaust the available part of the element or elements 

 which it requires in largest proportion, besides causing 

 other injurious effects noticed further on. 



The fungous parasites which attack particular species 

 of plants are multiplied from year to year if plants of 

 this species are continuously grown on the same soil, 

 while, if other species which are immune to these para- 

 sites are alternated with the host plants of such parasites, 

 the latter fail to be reproduced and disappear. Nearly 

 all insects confine their depredations to particular species 

 of plants, and as these insects hibernate in or near the 

 soil on which their food plants have grown, they become 

 more destructive as they are multiplied by their favorite 

 pasturage. The Colorado potato beetle did not multiply 



